Bern trial opens against transport firm head over contaminated fill at Mitholz quarry

The trial opens

On 4 November 2026 the head of a Bern transport company appeared before the economic criminal court in Bern, which heard the first trial on the main question of the Blausee affair. The case is a side track of the wider "Causa Blausee", a long-running legal dispute in which the owners of the trout farm are involved. The man faces charges of fraud, qualified property damage and violations of the water protection law. The property damage charge involves material worth 835,000 francs, while RTS puts the damage at more than 800,000 francs. The verdict is expected on 10 November, and the presumption of innocence applies.

How the alleged scheme worked

Prosecutors say the company accepted inert waste and press sludge from two construction firms in canton Zurich and billed them the higher price for legal disposal. Instead of disposing of the material properly, the drivers were allegedly told to relabel the loads as clean and haul them to the Mitholz quarry. There the disposal fee was 8 francs a tonne rather than 20. At the hearing the accused told the court that proximity made the quarry attractive, since his trucks could be loaded on both the outward and return trips. He admitted knowing the material could contain slight contamination, such as concrete residues, but said he could not imagine it had caused serious harm. RTS reports that the scheme netted him 90,000 francs.

Illegal route (Mitholz quarry)8

Legal landfill20

Illegal route (Mitholz quarry)

8 CHF per tonne

Legal landfill

20 CHF per tonne

Data from the article text

Thirteen truck drivers have already been convicted by penalty order, according to RTS. The accused has also been charged with repeatedly falsifying delivery documents.

Fish deaths and the quarry's location

The Mitholz quarry lies in a groundwater protection zone, where only unpolluted excavation may be used to backfill it. It sits about 1.5 kilometres above the Blausee trout farm. Tens of thousands of trout died at the farm, and SRF reports that thousands have died since 2018. The owners are convinced the deaths are linked to the deposited material, but SRF notes that this claim has not been proven to date. Quarry operator Vigier disputes any link between the quarry and the fish deaths. RTS reports that a separate strand of the case will still have to determine the environmental impact on the waters of the Blausee.

Earlier cases and the investigation

The quarry had already drawn scrutiny in 2020, when it emerged that it had been illegally used as a dump for contaminated material from the BLS construction site at the Lötschberg tunnel. Those proceedings produced no criminal consequences and were dropped in 2025, with the Bern prosecutor's office arguing that the responsible persons could not have known contaminated material was not allowed there. The current scheme came to light through investigations by SRF's Rundschau and Tamedia newspapers in 2021. Bernese authorities confirmed at the time that material had been deposited in violation of legal requirements.

What happens next

The trial continues on Thursday, 5 November, with the verdict expected on Tuesday, 10 November. Prosecutors have asked for two years in prison, suspended. The charges against the man include fraud, repeated document forgery, qualified property damage and breaches of the water protection act.